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Gatorman
38

Gatorman 38

Well I had hoped to become somewhat of a knowledgeable person on shark teeth but after trying to keep up with this thread and getting numerous headaches trying to learn something new I have begun to realize it may be too much for me. And on top of all this there seems to be some uncertainty with some teeth one person says this in their book and yet another claims that, does any of these guys really know what they are saying? This Kent guy, what was his book called? I would like to get a copy it seems he is your expert you repeatedly refer to for most species.

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Northern Sharks 134

Northern Sharks 134

Well I had hoped to become somewhat of a knowledgeable person on shark teeth but after trying to keep up with this thread and getting numerous headaches trying to learn something new I have begun to realize it may be too much for me. And on top of all this there seems to be some uncertainty with some teeth one person says this in their book and yet another claims that, does any of these guys really know what they are saying? This Kent guy, what was his book called? I would like to get a copy it seems he is your expert you repeatedly refer to for most species.

His name is Bretton Kent and the book is Fossil Sharks of the Chesapeake Bay Region. It may sound kind of localized, but the descriptions tell where teeth have been found worldwide and it does feature great illustrations of all species mentioned, with multiple pictures showing different tooth positions. There are several diagrams of complete dentitions. It really is a great reference book. The bible is probably Cappetta's Handbook of Paleoicthyology, but that is a pricey one if you can find it.

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Northern Sharks 134

Northern Sharks 134

Here's another link people may find useful. I don't know the background of the person who compiled this and I can't say for sure how complete it is, but it tells what teeth have been found in what locations and is probably the most complete listing of it's kind. The only thing it needs would be photos.

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Gatorman
38

Gatorman 38

The listing you provided is Georges, he is a cool guy Cris and I met in Gainesville he's the one who showed us a few good spots but have since not been producing well not for larger teeth anyhow. I will look into those two books I doubt I could afford either but we will see. I have Joe Cockes book Fossil shark teeth of the world but it lacks good descriptions and the pictures are fuzzy.

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Harry Pristis
2,317

Harry Pristis 2,317

Well I had hoped to become somewhat of a knowledgeable person on shark teeth but after trying to keep up with this thread and getting numerous headaches trying to learn something new I have begun to realize it may be too much for me. And on top of all this there seems to be some uncertainty with some teeth one person says this in their book and yet another claims that, does any of these guys really know what they are saying? This Kent guy, what was his book called? I would like to get a copy it seems he is your expert you repeatedly refer to for most species.

Hi, Anson . . .

Don't be too discouraged by this problem. When I first looked at these teeth, they all looked the same to me. Now, I think I can see subtle differences . . . sometimes. LOL

This complex of sharks has been a target of taxonomists for many years, and it's not sorted out yet. One struggle among taxonomists is between "the Lumpers" and "the Splitters"; the Lumpers want to simplify things with more-inclusive taxa, while the Splitters want to erect more and more taxa. When the systematics are uncertain, the Splitters seem to prevail.

Nonetheless, a taxonomist going to print does review the findings of earlier workers. Kent does so in his book, though his opinions are subject to later revisions. Elasmo.com is the most current review of these shifting ideas that I have seen.

My particular group of teeth has no provenance other than "Morocco," so age has to be deduced from the teeth. With other teeth, the collecting data may be useful in IDing a tooth. For example, if I find a shark tooth in the Santa Fe River below say Rum Island, I can be 99+% certain that is is a Late Eocene shark that is represented.

Learning about these extinct genera of sharks is much more difficult than learning about Miocene sharks, most of which still have representatives swimming in some ocean (even Hemipristis lives today in the Indian Ocean, I understand).

The Kent book is FOSSIL SHARKS OF THE CHESAPEAKE BAY REGION by Bretton W. Kent (1994). It is a very useful book which deals with a good number of Late Cretaceous through Tertiary taxa. The illustrations are line drawings which are often more useful than photos for identifications.

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Harry Pristis
2,317

Harry Pristis 2,317

Ok I ordered Kent's book i was surprised how expensive it was on amazon and abe books I found it on buried treasure fossils site for less that a third of what everyone else wanted.

Good for you, Anson! You should buy several as an investment. Out of print collector books (the authoritative ones, not the field or price guides) tend to increase in value.

Now that we have Anson on the road to confusion and frustration, here is my latest effort to sort out the Moroccan teeth. Four of the five sets of teeth seem to fit comfortably into species which lived in the Early Eocene. (We've already discussed the fifth set, the problematic "Cretodus" which should be Upper Cretaceous and is therefor not a good fit in this group.)

What do you think?

-------Harry Pristis

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Northern Sharks 134

Northern Sharks 134

Harry: The top left tooth in the Brachycarcharias pic looks to have a different root than the others. Could it be an anterior C. biauriculata? The 2 groups of Cretolamna seem to be correct. As for the other 2, other than the aforementioned tooth, they all look like S. aschersoni or S.gafsana to me just having different numbers of cusps. Of course, I just found out about S.gafsana since this thread started. The pictures on elasmo.com of Brachycarcharias all seem to have a narrower main crown. Moving to something easier, yes Hemipristis elongatus is still swimming in the indo-pacific. They reach a max. size of about 2.4 meters (much smaller than their forefathers). I've attached a couple of pics of a very large modern jaw with a 1 7/8 inch fossil H.serra for comparison.

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Harry Pristis
2,317

Harry Pristis 2,317

Harry: The top left tooth in the Brachycarcharias pic looks to have a different root than the others. Could it be an anterior C. biauriculata? The 2 groups of Cretolamna seem to be correct. As for the other 2, other than the aforementioned tooth, they all look like S. aschersoni or S.gafsana to me just having different numbers of cusps. Of course, I just found out about S.gafsana since this thread started. The pictures on elasmo.com of Brachycarcharias all seem to have a narrower main crown. <snip>

I have no problem removing the sole frontal tooth from the group of "Brachycarcharias" teeth, adding it to the group of Cretolamna biauriculata maroccana teeth.

S. aschersoni is what I originally called these teeth! I certainly saw and still see the resemblance. Anyone else think that the five teeth are Serratolamna aschersoni? S. aschersoni fits the Early Eocene time-frame I'm working with now.

I thought Brachycarcharias lerichei was a reasonable ID for the group of six (now five) teeth because they seemed to best resemble the rear upper laterals from the Nanjemoy and Castle Hayne illustrated on elasmo.com at ELASMO-GENERA-PALEOGENE[

Judging from the elasmo account, this taxon ranged from the Late Paleocene to Late Eocene (Bartonian) and is "reported from the Eocene of Morocco." I could find no further reference to this African version of the second Brachycarcharias tooth-design found in the Castle Hayne (Lutetian/Bartonian).

I grant you, there is some interpolation required here, but the Brachycarcharias tooth form seems to be somewhat plastic over time. I see a resemblance to those rear, upper laterals in the artificial tooth-set from the Nanjemoy.

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Northern Sharks 134

Northern Sharks 134

I have no problem removing the sole frontal tooth from the group of "Brachycarcharias" teeth, adding it to the group of Cretolamna biauriculata maroccana teeth.

S. aschersoni is what I originally called these teeth! I certainly saw and still see the resemblance. Anyone else think that the five teeth are Serratolamna aschersoni? S. aschersoni fits the Early Eocene time-frame I'm working with now.

I thought Brachycarcharias lerichei was a reasonable ID for the group of six (now five) teeth because they seemed to best resemble the rear upper laterals from the Nanjemoy and Castle Hayne illustrated on elasmo.com at ELASMO-GENERA-PALEOGENE[

Judging from the elasmo account, this taxon ranged from the Late Paleocene to Late Eocene (Bartonian) and is "reported from the Eocene of Morocco." I could find no further reference to this African version of the second Brachycarcharias tooth-design found in the Castle Hayne (Lutetian/Bartonian).

I grant you, there is some interpolation required here, but the Brachycarcharias tooth form seems to be somewhat plastic over time. I see a resemblance to those rear, upper laterals in the artificial tooth-set from the Nanjemoy.

That's the perfect term for what you're teeth are Harry There is one photo on elasmo.com, a lower lateral from the Nanjemoy formation that does have a wider crown, while all the others seem to be narrower. One last reference for you: on pg135 of Kent's book,in his references,is one from C. Arambourg (I won't type all the french) but it is described as "The most complete reference to the fossil sharks of Morocco" If you can find that, it might be of use. Best of luck.

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Harry Pristis
2,317

Harry Pristis 2,317

That's the perfect term for what you're teeth are Harry There is one photo on elasmo.com, a lower lateral from the Nanjemoy formation that does have a wider crown, while all the others seem to be narrower. One last reference for you: on pg135 of Kent's book,in his references,is one from C. Arambourg (I won't type all the french) but it is described as "The most complete reference to the fossil sharks of Morocco" If you can find that, it might be of use. Best of luck.

Arambourg's book (1952) is not easily found. I've been keeping my eye out for one for a very long time.

So, do you now prefer S. aschersoni for this group of five teeth, or are you comfortable with Brachycarcharias? I am ambivalent about this now, thinking I should go back to the original diagnosis of S. aschersoni.

It's not important in the overall scheme of things, I understand. It's merely the satisfaction of working out a puzzle, like the challenge of a jig-saw puzzle. Thanks for your help.

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Northern Sharks 134

Northern Sharks 134

Arambourg's book (1952) is not easily found. I've been keeping my eye out for one for a very long time.

So, do you now prefer S. aschersoni for this group of five teeth, or are you comfortable with Brachycarcharias? I am ambivalent about this now, thinking I should go back to the original diagnosis of S. aschersoni.

It's not important in the overall scheme of things, I understand. It's merely the satisfaction of working out a puzzle, like the challenge of a jig-saw puzzle. Thanks for your help.

-------Harry Pristis

I don't think anyone would fault you for saying they are S. aschersoni. The Brachycarcharias is another fairly new species for me as well. Until this thread started, I hadn't given them much thought, and as I said earlier, S. gafsana is a totally new species to me. I think I would like to see more examples of each before I could differentiate between them with reasonable confidence. This has been a great learning experience for me though and for that I thank you Harry.

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Harry Pristis
2,317

Harry Pristis 2,317

I don't think anyone would fault you for saying they are S. aschersoni. The Brachycarcharias is another fairly new species for me as well. Until this thread started, I hadn't given them much thought, and as I said earlier, S. gafsana is a totally new species to me. I think I would like to see more examples of each before I could differentiate between them with reasonable confidence. This has been a great learning experience for me though and for that I thank you Harry.

ps Cris: I agree with Harry-great teeth

I found one more of these teeth from the group. Tomorrow, I may redo the image of these teeth including the last one, and excluding the Cretolamna frontal tooth.

I don't worry about the S. gafsana ID because I'm confident that Serratolamna is at least the proper genus. I can't say that for the S. aschersoni/Brachycarcharias teeth at this point.

I understand your hesitation. I feel better for the struggle with these ideas. I alway feel good when I learn something. Thanks for the guidance.

----Harry Pristis

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Harry Pristis
2,317

Harry Pristis 2,317

Well, I've looked at these teeth once again, including the sole right upper (assuming these are all uppers) I located yesterday. I cannot find any substantial difference between these teeth and the three teeth I earlier identified as Serratolamna gafsana. Using Occam's Razor, I have shaved the number of species represented by these teeth to ONE -- S. gafsana. Here they are.

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Harry Pristis
2,317

Harry Pristis 2,317

That was such a nice close to this thread, NS, that I hesitate to post anything more to it. OTOH, I'd like this deliberation to stay in one thread to be coherent and useful.

I rummaged through many Moroccan shark teeth this weekend, and brought home a few. I want to apply what I have learned to these new acquisitions. I know that some on the teeth (e.g. Squalicorax pristodontus) are from the Cretaceous-age phosphates.

I'd like to post some images here so that anyone can critique my IDs before I put them in an image gallery. Here's the first one, a very large Cretolamna appendiculata or a "normal size" Otodus obliquus lateral. I think it must be O. obliquus.

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Harry Pristis
2,317

Harry Pristis 2,317

That was such a nice close to this thread, NS, that I hesitate to post anything more to it. OTOH, I'd like this deliberation to stay in one thread to be coherent and useful.

I rummaged through many Moroccan shark teeth this weekend, and brought home a few. I want to apply what I have learned to these new acquisitions. I know that some on the teeth (e.g. Squalicorax pristodontus) are from the Cretaceous-age phosphates.

I'd like to post some images here so that anyone can critique my IDs before I put them in an image gallery. Here's the first one, a very large Cretolamna appendiculata or a "normal size" Otodus obliquus lateral. I think it must be O. obliquus.

-------Harry Pristis

Well, I've sorted through this new batch of Moroccan shark teeth, and I believe I have a handle on these Lamniform teeth from the Ypresian.

Now, I find I have surplus teeth of several species. Here are three sets of teeth I've assembled from the larger group. Each group is comprised of one Cretolamna biauriculata maroccana, one Serratolamna aschersoni, and two Cretolamna appendiculata teeth. Each styrene plastic box has a label on the reverse.

If anyone needs a set of these teeth for his or her type collection, let me know.

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Northern Sharks 134

Northern Sharks 134

That was such a nice close to this thread, NS, that I hesitate to post anything more to it. OTOH, I'd like this deliberation to stay in one thread to be coherent and useful.

I rummaged through many Moroccan shark teeth this weekend, and brought home a few. I want to apply what I have learned to these new acquisitions. I know that some on the teeth (e.g. Squalicorax pristodontus) are from the Cretaceous-age phosphates.

I'd like to post some images here so that anyone can critique my IDs before I put them in an image gallery. Here's the first one, a very large Cretolamna appendiculata or a "normal size" Otodus obliquus lateral. I think it must be O. obliquus.

-------Harry Pristis

Harry: I saw this photo in the gallery, but failed to notice it here. I just wasn't looking at this thread pinned at the top of the category. Anyway, I agree with your label that it is a normal sized, very nicely colored Otodus tooth. If you have any surplus Moroccan teeth in that dark color, shoot me a PM. I'd love to get some of them to contrast with the regular cream colored examples I have.

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Harry Pristis
2,317

Harry Pristis 2,317

Nooo, Anson, I don't usually give away fossils to grownups! I suspect that people don't respect the things in which they are not somehow invested. But, I'm almost giving them away when I look at some prices on-line.

Apparently when Glikman (1958) named the genus, he intended to spell it Cretolamna. But in his paper, when he first introduced the name in the systematic paleontology section, he mispelled it as "cretalamna". So, it appears that Cretalamna is now being recognized as the actual name, since it has precedent. Recent publications such as Shimada (2007; JVP 27:3) use the now correct name Cretalamna. There was a posting on Elasmo.com a while back about this (last summer?), which a scan of Glickman's typo.